golf ball in a nest

Although quite peripheral to this thread maybe, I can’t help telling you about my experience back in 1980 (time flies!) somewhere in the State of Washington, USA: close to a golfcourse I stumbled across the nest of a Killdeer, that to my great surprise contained two killdeer eggs and a golf ball! The bird defended its nest vigorously, with all the tricks that plovers possess in this regard. Wim Vader, Tromsoe, Norway